1. Field of the Invention
The present invention relates to an automated guided vehicle that travels unmanned and improves the transfer and unloading of materials (articles) to be transferred.
2. Description of the Related Art
Conventionally, an automated guided vehicle (AGV) is known in which a conveyor for transferring materials to be transferred is provided on a dolly that travels unmanned. The conveyor transfers materials in an anteroposterior direction of the dolly. As shown in FIGS. 8A to 8C, automated guided vehicles 101 in conventional examples are driven to a terminal (end) of a belt conveyor 102 and are stopped. A material to be transferred 103 that is carried out from the terminal of the belt conveyor 102 is transferred onto a conveyor 104 provided on an upper surface of the automated guided vehicle 101.
Specifically, at the same time as the material to be transferred 103 is carried out from the belt conveyor 102 toward the automated guided vehicle 101, the conveyor 104 of the automated guided vehicle 101 is operated in synchronism with this belt conveyor 102, thereby transferring the material to be transferred 103 onto the conveyor 104 of the automated guided vehicle 101. Further, when the material to be transferred 103 transferred onto the conveyor 104 has moved to a vicinity of the center of the automated guided vehicle 101, the conveyor 104 is stopped. In this state, the automated guided vehicle 101 is caused to travel toward a next target, thereby the material to be transferred 103 is transported to that place.
The external size and the weight of the various materials to be transferred 103 that are transferred as described above are not fixed. A large-sized conveyor 104 is provided on the automated guided vehicle 101, as shown in FIG. 8A, and a small-sized conveyor 104 is provided on another automated guided vehicle 101, as shown in FIG. 8B. It is conceivable to selectively use these automated guided vehicles 101 having different specifications in accordance with the external size and the weight of the materials to be transferred 103.
It is difficult to make uniform the external size and the weight of the materials to be transferred 103 that are carried out from one belt conveyor 102. When the automated guided vehicle 101 provided with the small-sized conveyor 104 is used to receive a large material to be transferred 103, the material to be transferred 103 is too large to be transferred onto the small-sized conveyor 104. In this case, since the automated guided vehicle 101 must be replaced by one provided with the large-sized conveyor 104, extra time and labor are spent correspondingly.
Alternatively, when a small material to be transferred 103 is loaded on the large-sized conveyor 104 as shown in FIG. 8B, it becomes difficult to load other materials to be transferred (not shown) around the small material to be transferred 103. In other words, most of the loading space of the conveyor 104 becomes a dead space on which other materials to be transferred cannot be loaded.
In addition, as shown in FIG. 8C, to make utmost use of the loading space of the large-sized conveyor 104, an attempt may be made to load two or more materials to be transferred 103 in tandem in the transferring direction on one side of the large-sized conveyor 104. However, if an attempt is made to operate the conveyor 104 to load still other materials to be transferred (not shown) in the loading space adjacent to these materials to be transferred 103, the illustrated materials to be transferred 103 already loaded on the conveyor 104 fall off the automated guided vehicle 101.